This invention relates generally to improvements in filter bags for use with automatic pool cleaning devices, particularly of the type designed for submerged travel along the floor and subsurface sidewalls of a swimming pool to collect and dislodge debris. More particularly, this invention relates to an improved filter bag designed for improved operating efficiency of the pool cleaner and for facilitated removal of collected debris from the filter bag.
Residential and commercial swimming pools conventionally include water filtration systems designed for removing dirt and debris from the pool water. Such filtration systems include a circulation pump for pumping pool water through a filter unit which separates dirt and other suspended debris from the water, after which the pool water is returned to the swimming pool. To maintain desired standards of water cleanliness and clarity, such filtration systems are normally required to be operated on a daily schedule for at least several hours each day.
While a swimming pool filtration system for the type described above is esential for maintaining water cleanliness and clarity, such filtration systems by themselves are generally unable to maintain the pool water is a satisfactory state of cleanliness over a long period of time. For example, a conventional water filtration system is designed to remove suspended water-entrained debris of a relatively small size and not for removing larger debris, such as leaves and the like, or other particulate matter which tends to settle irrespective of size onto the floor and sidewalls of the pool. Accordingly, periodic cleaning of the pool floor and sidewalls by additional means is required to maintain the pool in a clean condition.
In recent years, a variety of in-the-pool cleaning devices have become popoular for dislodging and collecting debris and sediment from the floor and sidewall surfaces of a swimming pool. See, for example, the pool cleaning device shown and described in U.S. Pat. No. 3,822,754 which is adapted for sumberged and generally random travel along the pool floor and sidewalls, wherein such devices are exemplified by the pool cleaner manufactured and sold by Polaris Vac-Sweep of San Marcos, California, under the trademark POLARIS VAC-SWEEP. Cleaning devices of this type are designed for connection to a supply of water under pressure, such as by connection to the discharge side of a filtration system circulation pump, and are driven hydraulically over submerged pool surfaces to dislodge sediment and further include hydraulic suction means for drawing sediment and debris through a suction mast into a porous collection of filter bag.
In general, filter bags for pool cleaners have been formed from a meshlike material sewn into a shape having a lower open mouth for attachment about the upper end of the pool cleaner suction mast. Accordingly, water drawn upwardly into the filter bag passes through the meshlike material for return to the pool whereas water-entrained debris is trapped and collected within the bag. However, in previous filter bags, debris has tended to collect within the bag in a position obstructing water flow from the suction mast thereby inhibiting cleaner effectivity. This problem is compounded by the fact that the collected debris tends to fall back through the suction mast into the swimming pool upon cessation of cleaner operation. Moreover, previous collection bags have commonly included a stitched seam or the like closing the upper end of the bag, wherein this seam also interferes with and partially obstructs upward water flow from the suction mast to reduce cleaner efficiency. Still further, previous filter bags generally have been shaped with a relative broad front profile resulting in significant drag as the bag and cleaner move together through the pool water, wherein this drag can be sufficient to tip the cleaner and prevent desired suction operation. In addition, when collected debris is emptied from the filter bag, it has generally been necessary to remove the bag from the pool cleaner resulting in potential debris spillage onto the pool cleaner, wherein the spilled debris can contact cleaner drive machanisms and undesirably interfere with proper operation thereof.
There exists, therefore, a significant need for an improved filter bag for pool cleaners, wherein the filter bag is designed for improved hydraulic operating characteristics and for facilitated bag emptying, particularly without requiring bag removal from the pool cleaner.